Monton Chaowalit, Suksaeree Jirapornchai, Luprasong Chitradee
Drug and Herbal Product Research and Development Center, College of Pharmacy, Rangsit University, Pathum Thani 12000, Thailand.
Department of Pharmaceutical Chemistry, College of Pharmacy, Rangsit University, Pathum Thani 12000, Thailand.
Scientifica (Cairo). 2020 Mar 14;2020:6424682. doi: 10.1155/2020/6424682. eCollection 2020.
This work sought to validate the reversed-phase ion-interaction high-performance liquid chromatography for quantifying the nitrate content in the extract and raw material of (Willd.) Hook. f. ex Benth. leaves. Three extraction methods (i.e., decoction, infusion, and ultrasound-assisted extraction) were investigated and compared. Furthermore, the effect of the solid-to-solvent ratio and defatting was also evaluated. The validation result showed that the high-performance liquid chromatographic method had a linear response ( = 0.9999) in the range of 1-50 g/mL. The limit of detection and limit of quantitation were 0.25 g/mL and 0.75 g/mL, respectively. In addition, the method was specific, precise, and accurate. So the validated method was suitable for determination of the nitrate content in leaves. Infusion of a nondefatted sample using a solid-to-solvent ratio of 1 : 10 gave the highest nitrate content in the raw material, 0.251 ± 0.003%. In case of a defatted sample, decoction provided the highest nitrate content, 0.309 ± 0.001%. Increasing the solid-to-solvent ratio and defatting had a huge effect on the nitrate content of leaves extracted from decoction. To the best of our knowledge, this is the first report that used the reversed-phase ion-interaction high-performance liquid chromatography for quantifying the nitrate content in leaves. Furthermore, the authors suggested that nitrate could be used as a standard marker for quality control of leaves' extract and raw material.
本研究旨在验证反相离子对高效液相色谱法用于定量测定（Willd.）Hook. f. ex Benth.叶提取物和原料中的硝酸盐含量。研究并比较了三种提取方法（即煎煮法、浸泡法和超声辅助提取法）。此外，还评估了固液比和脱脂处理的影响。验证结果表明，高效液相色谱法在1 - 50μg/mL范围内具有线性响应（r = 0.9999）。检测限和定量限分别为0.25μg/mL和0.75μg/mL。此外，该方法具有特异性、精密度和准确性。因此，经过验证的该方法适用于测定（Willd.）Hook. f. ex Benth.叶中的硝酸盐含量。使用固液比为1∶10的未脱脂样品浸泡法得到的原料中硝酸盐含量最高，为0.251±0.003%。对于脱脂样品，煎煮法得到的硝酸盐含量最高，为0.309±0.001%。增加固液比和进行脱脂处理对煎煮法提取的（Willd.）Hook. f. ex Benth.叶中的硝酸盐含量有很大影响。据我们所知，这是首次使用反相离子对高效液相色谱法对（Willd.）Hook. f. ex Benth.叶中的硝酸盐含量进行定量的报道。此外，作者建议硝酸盐可作为（Willd.）Hook. f. ex Benth.叶提取物和原料质量控制的标准标志物。
